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Velocity loss in 223 Rem with carbine barrel lengths?

Discussion in 'Rifle Country' started by Balrog, Feb 26, 2010.

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  1. Balrog

    Balrog Member

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    Does anyone know approximately how much velocity you lose with a 16" barrel length as about to say a 20"?
     
  2. Birdhunter1

    Birdhunter1 Member

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    200 fps.
     
  3. NCsmitty

    NCsmitty Member

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    Last edited: Feb 26, 2010
  4. benEzra

    benEzra Moderator Emeritus

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    Here's a chart from M4carbine.net comparing a 20" M16, 16" civilian carbine, and 14.5" M4:



    [​IMG]



    BTW, the "fragmentation threshold" reference is to military FMJ, not civilian SP's or JHP's, which will expand/fragment reliably at much lower velocities than 2700fps.
     
  5. Al LaVodka

    Al LaVodka member

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    I have often gotten disbelief from people who don't know the M4 is shorter than our AR Carbine's and that we have a slight advantage with one that is 10% longer.

    :rolleyes:

    Al
     
  6. Ughh

    Ughh Member

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    That chart is weird... M16 is 16'' right? How is it faster than the following '16''' column?
     
  7. Runningman

    Runningman Member

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    The M16 uses a 20" barrel.

    That chart is also very close to the difference I got between a Colt AR 20" HBAR and another Colt AR, 16" 6721. Using winchester USA 55 grain load on a slightly warm 82 Deg F day. I recorded 3263 FPS out of the 20" Colt. VS 3132 FPS out of the 16" Colt. For a difference of 131 FPS.
     
  8. Ughh

    Ughh Member

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    Holy cow! I was always under the impression that the M16 was 16''. Stupid me :p
     
  9. taliv

    taliv Moderator

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    however, if you hang around the reloading forums, or people who own chronographs, you'll find that

    1) 20 different rounds from the same lot of ammo may have more than 100 fps difference between the fastest and slowest measured

    2) the average speed (constant ammo) through individual barrels of the same length may vary by 100 fps due to differences in chambers, rifling, lining, etc


    i mostly just work on trigger control these days
     
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